Sodium arc lamps

Sodium Arc Lamp—The Unitized Sodium Lab Arc is furnished with the instrument. 

Light Source, Sodium Arc Lamp—The light source shall be a sodium arc lamp, which shall be used only after the removal of Amici compensating prisms, if there are any present in the instrument. 

Adjust the thermostat so that the temperature as indicated by the thermocouple inserted between the prism faces and wet with oil is within 0.2 C of the desired test temperature. This temperature is to be held constant to within 0.02°C during the test. Observe and record the thermometer reading corresponding to the test temperature. Turn on the sodium arc lamp and allow it to warm up 30 min. 

Technical limits of exitance also impose minima for the dimensions of medium-pressure light sources (length of arc, length and diameter of bulb), for example, medium-pressure (doped) mercury arcs, high-pressure sodium vapor lamps, and incandescent lamps. 

Resist films (1-2 microns) containing t-butoxycarbonate protected phenolic resin and appropriate onium salt photoinitiators were spin coated on quartz wafers (UV analysis), sodium chloride plates (IR) and silicon wafers (imaging). Near-siirface irradiation with deep UV light was performed with a mercury-arc lamp through 200 and 220 nm bandpass filters (Oriel). 

The addition of electrodes and possibly an easily volatilized and ionized metal to the most basic lamp design creates an arc pathway through an ionizable gas. This produces a single element arc lamp like those of mercury, sodium, and xenon. Their emission spectra primarily is that of the pure element. Because of the intense heat generated by the arc, electrodes and impurities vaporized and ionized, all of which contribute to the overall spectral power distribution (SPD) of the lamp. This effect is more probable for short-arc (less than 5 mm distance between electrode tips) than the long-arc types. 

The yellowish glow of some highway lamps is due to a sodium arc. Mercury lamps give a bluish glow. 

In addition, since most of their compounds would duplicate analogous sodium and potassium compounds, there are relatively few commercial uses of rubidium or cesium. In areas in which they do find application, generally speaking, cesium is preferred over rubidium. Cesium, and to a lesser extent rubidium, is used in photocells, televisions, motion picture equipment, and luminescent screens. Cesium is also used in spectrographic instruments and vapor arc lamps. 

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